Thermoplastic composite building product having continuous fiber reinforcement

ABSTRACT

The present invention relates to a decking product, such as railing, fencing, posts and decking, made in part from commingled continuous filaments of glass fibers and polymeric fibers. The commingled fibers can be consolidated into a composite reinforcement or final profile, and can be used in the form of bulk molding compound pellets. The consolidation of the commingled fibers into a composite reinforcement can be made in-situ, during in-line extrusion of the final end product, profile, or extrudate, or prepared as a tape or rod and later incorporated into an off-line extrusion of final product. The bulk molding pellets can be used solely or diluted with an addition of polymeric material for extrusion, co-extrusion, or compression molding, for example.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. Ser. No.09/988,985, filed Nov. 19, 2001 (D0932-00178), U.S. Ser. No. 10/281,796,filed Oct. 28, 2002 (D0932-00220); U.S. Ser. No. 10/281,795, filed Oct.28, 2002 (D0932-00200), and U.S. Ser. No. 10/441,530, filed May 19, 2003(D0932-00393), which are all hereby incorporated by reference in theirentirety. Pursuant to MPEP §904, the Examiner is directed to inspect thecomplete files of these earlier applications for material informationconcerning the instant claims.

FIELD OF THE INVENTION

The present invention relates to a process for providing thermoplasticcomposite building products having fiber reinforcement, and moreparticularly, to the use of a consolidated form of the commingledcontinuous filaments of glass fibers and polymeric fibers as continuousor bulk reinforcement in building products, such as decking, fencing,railing and posts.

BACKGROUND OF THE INVENTION

Most fence and rail materials are made of either traditional lumber orthermoplastics. Typical plastics in these applications are PVC(polyvinyl chloride) and polyethylene. PVC typically does not have thestrength and rigidity of wood and lumber and therefore, the rail for thefence and railing needs a steel or aluminum reinforcement channel insidethe rail. These metal reinforcements are prone to corrosion attack, andlose strength in long-term endurance tests. There is also a thermalexpansion problem associated with the dark color of thermoplasticproducts. Dark color fencing rails made out of PVC or other polymericmaterials often exhibit bowing due to differences in expansion andcontraction between the two different sides of the product upon exposureof sunlight. Since the dark color absorbs heat more readily on thesun-facing side of the product, the resultant uneven heat buildup causesthe rail to deform. An additional problem is the lack of long-termstiffness of polymeric products. It has limited the rail span betweenthe posts to lengths less than traditional lumber rails.

Also, synthetic decks, whether composed of plastic or wood-plasticcomposite materials, do not fully satisfy market needs.

Wood-plastic composite decking planks are produced by extrusion, andextrusion processes have various limitations. Extrusion is oftenfollowed by an embossing roll to create a wood grain surface. Thequality of such wood grains is often not particularly high. Furthermore,the wood-plastic composite deck planks are heavy, since the woodcomposite has a low modulus and flexural strength, which needs a thickwall to compensate for these lower strength levels. In addition, thewood-plastic composite deck does not have color fastness; it changescolor from natural or gray to silver-gray over time, in a non-uniformmanner when exposed to the outdoor environment.

As noted above, there is another class of synthetic deck planksavailable, namely the PVC profile decks. Such decks are produced byprofile extrusion. In this type of production, it is often difficult touse an embossing roll to create the wood grain texture in a uniformnature on the deck surface. The pressure imposed by the embossing rolloften cannot provide a uniform force, because the surface of a hollowand three-dimensional panel responds in a non-uniform manner to theparticular force. As result, a “real wood” grain emulated surface isparticularly difficult to achieve. The PVC profile deck also has asignificant thermal expansion coefficient; installation requires care inorder to accommodate the expansion and contraction of changes intemperature. In this regard, the dark color deck panel materials havenot been practical, since the heat build-up on the surface, and theunwanted thermal expansion that results, is more pronounced for darkercolored panels. Regarding color fastness, the darker color PVC issuperior to wood-plastic composites, but still has the tendency to loseits original color to a visible degree. Furthermore, PVC has a tendencyto become brittle with aging upon outdoor exposure to the elements,particularly UV radiation, resulting in a loss of its impact strength.

The present invention serves to correct the shortcomings noted above.The building products produced in accordance with the present inventionhave superior resistance to color fading, possess superior cold impactstrength, have, in certain embodiments, a well-defined wood grainsurface, and are light-weight.

One of the further objectives of the present invention is the productionof a high strength plastic alternative to the traditional wrought ironor aluminum ornamental rail and fence. Metal fences and rails areconstantly under the threat of corrosive attack, and need periodicpainting. To date, there have not been any non-composite products withthe necessary performance properties and aesthetic appearance comparableto these metal products. In that sense, there have been very fewsuccessful thermoplastic composite products in the market.

Some of the recent teachings for producing reinforced polymeric articlesinclude Branca, U.S. 2004/0048055; Baker, U.S. 2003/0082338, and one ofthe parents to this application, Jo et al., U.S. 2003/0096090; Hassman,U.S. Pat. No. 3,983,688; Stucky, U.S. Pat. No. 6,344,268; Jambois, U.S.Pat. No. 6,197,412; Junell, U.S. Pat. No. 5,967,498, and TectonProducts, Innovative Composite Pultrusion Solutions commercial products,all cited in Applicants' parent applications and hereby incorporatedherein by reference.

The present invention discloses thermoplastic composite products thatresemble wrought iron, and wrought aluminum alternatives, but aremaintenance-free, kink-free, light weight and perform as well as wroughtmetal products.

An additional objective is to make the dark color thermoplastic post andrail fence (e.g., split post and rails) by providing a fiberglassreinforcement which stabilizes the uneven contraction and expansion ofoutdoor building products, in spite of different heat buildup on thesurfaces of such products.

A further objective of the present invention is to provide anon-metallic heavy duty rail and fence systems for use in industrial andcommercial applications. The metallic railing in an industrialatmosphere is often exposed to chemical gases or acids and is prone tocorrosive attack. The integrity of the industrial railing is criticalfor the safety of those in the workplace. A thermoplastic railing ordecking system that is strengthened by reinforcing tapes or rods offiberglass/thermoplastic polymer composite would provide superiorstrength and rigidity to its metal counterparts.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a deck construction using thepreferred composite;

FIGS. 2 and 3 are front perspective views of alternative deckconstructions;

FIG. 4 is a front partial view of a fence or railing construction usingthe preferred composite;

FIG. 5 is a frontal view of a post and rail fence;

FIGS. 1-13 are cross-sectional views of a fence construction using thepreferred composite building materials of this invention; and

FIG. 14 is a front partial view of an alternative post and rail fence.

SUMMARY OF THE INVENTION

In a first embodiment, the present invention provides a thermoplasticcomposite decking material including a molded thermoplastic compositeprofile made substantially from a bulk molding compound which is, inturn, made substantially from a co-mingled group of glass fibers andconsolidated thermoplastic fibers, which form a matrix around the glassfibers. The thermoplastic fibers used to make the bulk molding compoundare selected from the group consisting essentially of polyethylene,polypropylene, and (thermoplastic) polyester.

In a further embodiment of this invention, a polymer composite fencingor railing material is provided, which includes a compositereinforcement comprising filaments of fibers substantially oriented inat least a first direction substantially continuously along the entirelength of said fencing or railing material, and disposed within athermoplastic matrix. Disposed substantially over and in direct contactwith the composite reinforcements is a capstock polymeric material. Thefencing or railing material is resistant to heat deformation andcorrosion.

In still a further embodiment of the present invention, a process ofmaking a building component is provided which includes the steps ofco-mingling continuous glass and polymeric fibers wherein the polymericfibers are selected from the group comprising polyethylene,polypropylene, and polyester; consolidating said co-mingled glass andpolymeric fibers into a reinforcement; and disposing a polymeric layerat least partially over and in bonding contact with said reinforcement,said polymeric layer forming the profile for said building component.

In yet another embodiment of the present invention, a process of makinga building component is provided which includes the steps of co-minglingcontinuous glass and polymeric fibers, wherein the polymeric fibers areselected from the group comprising polyethylene, polypropylene, andpolyester, forming said co-mingled, continuous glass and polymericfibers into a bulk molding compound; and compression molding said bulkmolding compound into a building component profile.

The present invention relates to a process for providing thermoplasticcomposite building materials, such as railings, posts, and deckingprofiles with bulk molding compounds and/or continuous fiberreinforcement. Such products can be formed by consolidating commingledcontinuous filaments of glass fibers and polymeric fibers for use as areinforcement. The consolidation of commingled fibers into compositereinforcement may be made in-situ during in-line extrusion of the finalend product extrudate, or, alternatively, by pre-preparing as a tape orrod and incorporated the tape or rod by way of an off-line extrusioninto a final product. In either case, the reinforcement materials of thepresent invention are, preferably, incorporated through a cross-head dieinto the polymer extrudate. In this way, the matrix polymer canencapsulate the inside and outside surface of the hollow profileproduct.

Another production process contemplated by this invention is to passthese commingled fibers through a pultrusion die, followed by an overlayextrusion of a cap stock polymer using a separate extruder, all in-line.In this case, the capstock polymer covers only the outside surface. Thecommingled fibers are heated prior to entering into the series offorming dies where they are consolidated. In a further embodiment, ahelical winding machine may be added in order to enhance the strength inthe hoop direction before the die entrance.

A preferred material for use in the present invention is commerciallyavailable Twintex™ composite tapes, supplied by the Saint-GobainCorporation. The materials are present in various forms, such ascommingled roving and fabrics (uni-directional, or multi-axial wovenfabric or tapes). The commingled roving can be consolidated through apultrusion die into a thermoplastic composite tape or rod. It thereforemay contain glass fibers dispersed uniformly and substantiallycompletely along the longitudinal direction. The polymeric fiber thatbecomes the consolidation matrix may be either polyethylene (PE),polypropylene (PP) or polyesters (PBT or PET). The functional need ofthe end product and extrusion process will determine the fiberglasscontact in the Twintex™ material and the volume of the consolidatedreinforcement. A “standard” material contains about 40%-75% glass fibercontent.

Although polyethylene and polypropylene Twintex™ tapes were used in thetesting of the present invention, any fibrous polymeric material wouldbe acceptable for a commingling with glass fiber, as long as it iscapable of being fiberized and made compatible to the intended matrixpolymers.

A further aspect of the present invention relates to the compatibilityof the commingled polymeric fiber material with the matrix or capstockpolymer of the final extrusion product. These materials need adhesionwith each other in order to be effective, since they are, desirably,bonded or adhered to each other as shown in FIGS. 6-13, for example.Accordingly, there is little need for additional adhesive or surfacetreatment to effect this bond. In the testing of the present invention,a polyethylene-glass fiber Twintex™ reinforcement/HMPE polymer,polypropylene-glass fiber Twintex™ reinforcement/HMPE polymer,polyethylene-glass fiber Twintex™ reinforcement/polyethylene polymer,and polypropylene glass fiber Twintex™ reinforcement/polyethylenepolymer were used. The combinations of the polymers of the compositereinforcement and the base polymers are numerous, and may be customizedin order to meet the needs of the final product performancerequirements.

The Twintex™ composite reinforcement allows for the base polymericmaterial with a higher impact in both cold and ambient temperatures,lower heat expansion coefficient, higher tensile and flexural strength,as well as higher rigidity. These Twintex™ reinforcements (rods, tapes,or fabrics) are embedded into strategic locations of the basic polymericmaterial, for example.

In a further preferred embodiment of the present invention, a hybrid ofTwintex™ filaments with carbon fibers may be utilized, with thecombination providing for higher stiffness and for easier materialhandling, as well as providing for a lighter weight product.

Some of the materials of the present invention may be manufactured by apultrusion process, the mechanics of which are familiar to those ofskill in the art. The process utilizes continuous Twintex™ fibers(roving or yarn), and other fiber as necessary, in order to processuniaxially reinforced profiles with exceptional longitudinal strength.Modification of the basic process allows for the incorporation oftransverse reinforcements. Important components of the pultrusionprocess are: (1) heating, wherein the thermoplastic fibers are melted,and (2) the consolidation and shape forming at the tooling die, in whichrelatively high pressure is involved.

In a further preferred embodiment, the commingled, continuous filamentsof glass fibers and polymeric fibers include from about 40%-80% glassfiber content. These commingled, continuous filaments may furtherinclude carbon fibers and/or aramid fibers. Furthermore, a bulk moldingcompound may be made out of the commingled, continuous filaments ofglass fibers and polymeric fibers. This bulk molding compound may becompression molded into particular building products, such as fence,rail, post, and deck materials. The commingled, continuous filaments maybe added through, e.g., a helical winding machine.

In a further preferred embodiment of the present invention, the bulkmolding compound includes from about 20%-80% glass fiber content, or isdiluted with an addition of polymeric pellets to a glass fiber contentof 10%-20% in the final product, with a glass fiber content of about 15%preferred. The thermal expansion and contraction of the compositebuilding material can be controlled by the use of the bulk moldingcompound.

Wood-plastic composite panels commercially available have a stiffness ofabout 100,000 PSI. In order to match that stiffness, the presentinventors incorporated one half inch to one inch long fiberglass of 10%at minimum with a profile height of about 1.25 to 1.5 inches. Thesedimensions will result in the composite material having a flexuralmodulus of about 400,000 PSI or higher. In a preferred embodiment,polymeric materials, specifically polypropylene copolymers with a meltindex of about ten and higher, and formulated with a UV stabilizer andcolorant, were tested. Note that other polymeric materials may be usedfor the purposes of the present invention, so long as such materialshave an adequate melt index. Measurement of melt flow index wasdescribed in ASTM D1238. By incorporating fiberglass in the formulationby means of a bulk molding compound, the thermal expansion andcontraction was reduced so that the dark brown color was no longerpresent. The thermal coefficient of linear expansion was reduced by morethan ⅙, to about 1×10⁻⁵ inch/inch/° F. for the polypropylene copolymer.

In reference to the figures, FIGS. 1-3 demonstrate differing ways bywhich the decking panels and ties may be fastened to the substructure.In FIG. 2, screw fasteners 121 on the top of composite 120 provide thefastening function, while pins 122 act as spacers. The composites 110and 130, as shown in FIGS. 1 and 3 respectively, rely on a concealedfastener 114 with pin 111, which is formulated to key into the side hole112 or 131 of composite panels 110 and 130. The concealed fastener 114can be screwed into the substructure joist by screw 113. The concealedfasteners, such as screw 113, are also desirable for tiles.

Note that the preferred process for achieving the construction of thepresent invention is compression molding. The molding process provides awood grain pattern of high quality. In operation, a fiberglass bulkmolding compound is processed through a specially designed plasticator,and the billet is shuttled to a compression mold, and pressed. Notefurther that the plasticator is merely one type of compounding extruderequipped with a screw, designed to process the fiberglass in the bulkmolding compound without breaking the fiberglass. Panel lengths producedby the compression molding process may range up to about 20 feet. Thecompression molding enables the surface of the panels to have customizedpatterns, as well as slip resistance called for by various industrycodes.

Thus, the present invention relates to any walking panels or plankswhich have incorporated fiberglass of at least about ½ inch long, atabout 10% to 40% by weight into a polymeric material of a melt indexhigher than e.g., about 2, in order to improve the impact strength forboth “under room” and cold temperatures. Walking panels or planks withthese characteristics may be made into any suitable custom colors,particularly dark colors, and serve to meet relevant building codes,performance criteria, deflection and creep resistance. Furthermore, aquality grain structure is achieved on the surface of the walking panelsor planks, thereby controlling slip resistance.

The fiberglass component of the present invention may be choppedfiberglass, hybridized with other modulus enhancing fibers. In a furtherpreferred embodiment, the walking panels or planks may have incorporatedmold-in spacers, such as pin 122, for ease of installation. Furthermore,the panels or planks of the present invention may be constructed offiberglass bulk molding compound, using a compression molding processhaving a concealed fastener; such materials will make cutting easier bya power driven saw or other related device.

With reference to FIGS. 4 through 14 thereof, a picket and railingconstruction 100, a post and rail 200 and fence 300 will now bedescribed. Turning to FIG. 1, this partial post and rail constructionincludes rails 10 and 20, connected by balusters 11. Note thecross-sections 12 and 13 of rails 10 and 20 include Twintex™ rods 14 and15.

In FIG. 5, partial post and rail construction 200 includes rails 30 and40 connected by post 50. Note the cross sections 16 and 17 of rails 30and 40 and cross section 18 of post 50 include Twintex™ rods 19, 20 and21, respectively.

With reference to FIGS. 6 through 8, cross sections 12, 16 and 13corresponding to rails 10, 30 and 20 respectively are represented, withrelated Twintex™ rods 14, 19 and 15 as shown.

Similarly, in FIGS. 9-13, cross sections of various rails are displayed(60-64, respectively) along with Twintex™ rods (65-69, respectively).

Twintex™ may also be manufactured as a bulk molding compound (BMC) withfibers having a length of from about 3/16 inch to 2 inches. These longfibers may be processed through an extruder with a die that isspecifically designed for processing of long fiber reinforced plastics.These BMC compounds can be diluted with other polymeric pelletsdepending on the need of processability, functional demand, or costreduction.

In a further preferred embodiment of the present invention, a rail ofmore than an eight foot span between the two posts, on a sixteen footlength encompassing two sections with, e.g., three posts with a Twintex™reinforcement, is provided. The use of a hybrid reinforcement ofTwintex™ commingled fiber and other reinforcement fibers, such as carbonfiber and/or aramid fibers is also possible.

Thus, the bulk molding compounds used for purposes of the presentinvention may be employed for compression molding into building productsincluding fence, rail, post, deck, etc.

While this invention has been described with respect to particularembodiments thereof, it is apparent that numerous other forms andmodifications of this invention will be obvious to those skilled in theart. The present invention relates, in part, to a consolidated form ofthe commingled continuous filaments of glass fibers and polymericfibers. The consolidation of the commingled fibers into compositereinforcement can be used in a continuous form or bulk molding compoundpellets. The consolidation of the commingled fibers into composites canbe made in-situ during in-line extrusion of the final end productextrudate, or prepared as a tape or rod and incorporated into anoff-line extrusion of final product. The bulk molding pellets are usedsolely, or diluted with an addition of polymeric material, for mono orco-extrusion or compression molding.

The appended claims and this invention, generally, should be construedto cover all such obvious forms and modifications which are within thetrue spirit and scope of the present invention.

1. A thermoplastic composite decking material comprising: a moldedthermoplastic composite profile made substantially from a bulk moldingcompound containing commingled glass fibers and consolidatedthermoplastic fibers, wherein the thermoplastic fibers used to make saidbulk molding compound are selected from the group consisting essentiallyof polyethylene, polypropylene, and polyester.
 2. The decking materialof claim 1, further comprising a wood grain.
 3. The decking material ofclaim 2 wherein said wood grain is slip resistant.
 4. The deckingmaterial of claim 1, wherein said glass fibers are substantially atleast one half inch in length.
 5. The decking material of claim 1,wherein said glass fibers comprise about 10-40 wt. % of said deckingmaterial.
 6. The decking material of claim 1, wherein said deckingmaterial comprises a UV stabilizer and exhibits a custom color.
 7. Thedecking material of claim 6, wherein said custom color is a dark color.8. The decking material of claim 1, wherein the bulk molding compoundincludes about 20%-80% glass fiber content, or is diluted with anaddition of polymeric pellets to a glass fiber content of 10%-20% in thefinal product.
 9. The decking material of claim 8, wherein the thermalexpansion and contraction of said decking product is controlled by theuse of said bulk molding compound.
 10. The decking material of claim 9,wherein said decking material is a walking panel or plank, incorporatinga molded-in spacer or spacer hole.
 11. A polymer composite fencing orrailing material comprising: a composite reinforcement comprisingfilaments of fibers substantially oriented in at least a first directionsubstantially continuously along the entire length of said fencing orrailing material, and disposed within a thermoplastic matrix; and acapstock polymeric material disposed substantially over and in directcontact with said composite reinforcement; said fencing or railingmaterial being resistant to heat deformation and corrosion.
 12. Thefencing or railing material of claim 11 wherein at least said capstockhas a dark color.
 13. The fencing or railing material of claim 12wherein said heat deformation resistance includes resistance to bowingdue to expansion and contraction of said fencing or railing materialwhen exposed to sunlight.
 14. The fencing or railing material of claim13 wherein said composite reinforcement and said capstock are observablydiscrete portions of said fencing or railing material.
 15. The fencingor railing material of claim 11, wherein said composite reinforcementcomprises about 20 wt. % fiber content.
 16. The fencing or railingmaterial of claim 15 wherein said fibers comprise one or more of: glass,aramid, or carbon fibers.
 17. The fencing or railing material of claim11 wherein said fibers comprise continuous glass filaments, saidthermoplastic matrix comprises polypropylene, and said capstockcomprises high molecular weight polyethylene (HMPE).
 18. The fencing orrailing material of claim 11 in which the fencing or railing material isin the form of a fence, rail, post, or fencing or railing component. 19.The fencing or railing material of claim 11 further comprising asecondary group of fibers oriented in a second direction.
 20. A polymercomposite fencing component comprising: a composite reinforcementcomprising continuous filaments of high strength fibers orientedsubstantially in at least a first longitudinal direction within athermoplastic matrix; and a thermoplastic capstock polymeric material,which is itself adherent to the thermoplastic of said compositereinforcement, said capstock polymeric material disposed substantiallyover and in contact with said composite reinforcement; said fencingcomponent being resistant to corrosion and heat deformation due toexposure to sunlight.
 21. The fencing component of claim 20 wherein saidcomposite reinforcement comprises one or more of: roving, fabric ortape.
 22. The fencing component of claim 21 wherein said fabriccomprises a uni-directional, multi-axial or woven material.
 23. Thefencing component of claim 20 wherein said composite reinforcementcomprises a pultrusion.
 24. The fencing component of claim 20 whereinsaid polymeric matrix comprises polypropylene, said fibers comprisecontinuous glass filaments, and said capstock comprises high molecularweight polyethylene (HMPE).
 25. The fencing component of claim 20wherein said component has a dark color and a span of at least about 8feet.
 26. A polymer composite fencing component comprising: a compositereinforcement comprising continuous glass filaments of fiberssubstantially oriented in at least a first direction within a pultrudedthermoplastic polymeric matrix, said composite reinforcement having ahigher tensile strength than aluminum; and a thermoplastic capstockpolymeric material having a dark color disposed substantially over andbonded directly to said composite reinforcement; said fencing componentbeing corrosion resistant to chemical gasses or acids and resistant tobowing due to expansion and contraction of said fencing or railingmaterial upon exposure to sunlight.
 27. The fencing component of claim26 wherein said fibers are oriented in substantially only said firstdirection for substantially the entire length of said fencing or railingmaterial.
 28. The fencing component of claim 26 wherein said capstock isdirectly bonded to said composite reinforcement without additionaladhesive or surface treatment.
 29. A substantially maintenance freepolymer composite ornamental rail or fence component comprising: athermoplastic matrix composite comprising high strength glass filamentsdisposed substantially continuously along the entire length of said railor fence component; and a thermoplastic capstock polymeric materialhaving a dark color disposed substantially over and in direct contactwith said composite reinforcement, said rail or fence component beingsubstantially stabilized when exposed to uneven contraction andexpansion forces, despite a difference in heat buildup on its surfacedue to sunlight.
 30. The component of claim 29 wherein said polymer ofsaid polymeric matrix composite and said capstock both contain the samethermoplastic resin.
 31. The component of claim 29 wherein saidcomposite is a pultrusion.
 32. A process of making a building componentcomprising: (a) commingling continuous glass and polymeric fibers,wherein said polymeric fibers are selected from the group comprisingpolyethylene, polypropylene, and polyester; (b) consolidating saidcommingled glass and polymeric fibers into a reinforcement; and (c)disposing a polymeric layer at least partially over and in bondingcontact with said reinforcement, said polymeric layer forming theprofile for said fencing or railing component.
 33. The process of claim32, wherein said disposing step (c) comprises extruding said polymericlayer over said reinforcement.
 34. The process of claim 32 wherein saidconsolidating step (b) comprises pultruding said commingled glass andpolymeric fibers.
 35. A process of making a fencing or railing componentcomprising: (a) commingling continuous glass and polymeric fibers,wherein said polymeric fibers are selected from the group comprisingpolyethylene, polypropylene, and polyester; (b) forming said commingledcontinuous glass and polymeric fibers into a bulk molding compound; and(c) compression molding said bulk molding compound into a fencing orrailing component profile.